Conventionally, fabricating a TFT (Thin Film Transistor) array substrate for a color liquid crystal display device requires five to nine photomasks. As the number of photomasks to be used is increased, the number of the fabrication steps increases accordingly, and therefore the fabrication becomes complicated, making it difficult to reduce the fabrication cost.
Meanwhile, a technique for reducing the number of photomasks used in the fabrication process of a diode array substrate to two has been proposed (Published Japanese Translation of PCT International Publication for Patent Application No. 62-502361). However, the performance of diode array substrates is inferior to that of TFT (Thin Film Transistor) array substrates, and therefore the diode array substrate is not suitable for use in color televisions.